The invention relates to an end binder for a heald shaft.
Heald shafts are essential components of weaving machines. The heald shafts serve for shed-forming in which warp threads are guided from the warp thread assembly upward or downward, while others remain in a position of rest or are moved in an opposite direction. A weft thread is then introduced into the shed formed in this manner for obtaining the desired weave.
U.S. Pat. No. 4,022,252 discloses a heald shaft of the above-outlined type. It comprises an upper and a lower shaft rod which are horizontally oriented in use. Each shaft rod is provided with a shaft stave which supports the healds. Each heald has at least one yarn eyelet through which the warp yarn runs. At their ends the shaft rods are interconnected by end binders which are oriented vertically in use and which define a rectangular frame with the shaft rods. The end binders hold the shaft rods at a defined distance from one another and also assume guiding tasks.
The end binder known from the U.S. Pat. No. 4,022,252 comprises a plastic section body in which a cross-sectionally U-shaped sheet metal section is formed. A portion of the sheet metal section is freely exposed at the side facing away from the shaft rods and serves as a guiding section for a vertical sliding guide of the heald shaft. The material pair plastic/steel may be critical. Measures must be taken for preventing a separation of the metal section from the plastic body.
Japanese Patent Document No. 02068331 A discloses a light-weight heald shaft which includes an end binder formed of a combination of several layers of laminated thermoplastic materials and aluminum layers.
European Patent No. EP 0 297 003 B1 describes in FIG. 8 an end binder which is a thick-walled U-section and in which the section is open at the side facing away from the shaft rods. Such sections may be manufactured from aluminum in a milling or extrusion process.
German Patent No. 44 03 923 C1 discloses a tubular, box-section like end binder which is connected with the shaft rod of a heald shaft by corner joints. For driving the heald shaft, it is proposed that the corner joints include a driven part attached by rivets.
United States Published Patent Application No. 2002/004 0736 A1 discloses a solid-section end binder for a heald shaft. The end binder serves not only for holding and supporting the shaft rods, but also for driving the same. For this purpose the end binder is, at its side facing away from the shaft rods, provided with a groove receiving an endwise threaded bar. To the upper end of the end binder two plates are screwed which have a receiving slot for a coupling member which is screwed together with the threaded bar. The coupling member may be vertically displaceably guided on a guiding section to provide guidance for the heald shaft.
The slotted plates which are provided for attaching the end binder with the coupling member and the threaded bar, are screwed together with the solid section.
The manufacture of the above-described end binders involve substantial outlay and furthermore, their load-bearing capacity is limited.
It is therefore an object of the invention to provide an improved end binder.